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Noise barrier with acoustic metamaterial has application prospect in power transformer noise reduction due to its low frequency noise reduction advantages. The acoustic diffraction along the edges of the noise barrier decreases the overall noise reduction obviously. An active noise control (ANC) method combined with noise barrier is proposed to counteract the diffracting sound waves near the edges of the noise barrier. The noise barrier is composed of the Hilbert fractal acoustic metamaterial (HFAMM) units with good sound insulation characteristics at low frequencies. The transmission loss (TL) of the HFAMM unit is higher than 20dB at the main frequencies of the transformer noise theoretically. The experiment system including the acoustic metamaterial noise barrier and the ANC system is established. The sound pressure level with ANC on the specified points in the target area is more than 10dB lower than that without ANC in the experiment. The results prove that the new method is effective for improving noise reduction performance of the noise barriers.

Aiming at the problems of irregular operation, fragmentation of information, low coverage of operating equipment, unsatisfactory evaluation method and difficult to effectively guide operation and maintenance in infrared thermography and atlas diagnosis, the basic concept, theoretical basis, influencing factors and matters needing attention of infrared thermometry are expounded. It is proposed to construct the infrared thermal image database covering the transformer, transmission and distribution equipment as a unified software platform, and to store, classify and inquire according to the equipment type, voltage level, defect type, etc. The whole process of infrared temperature measurement is standardized and standardized. Intelligent identification and analysis method of atlas are expounded represented by curve analysis method that extracts important parameters from source atlas, and uses fuzzy logic, artificial neural network and support vector machine to realize the preliminary judgment of the result, which greatly improves the evaluation efficiency and diagnostic level. The infrared atlas analysis of transformer annular tubes is carried out.

In order to accomplish the environmental friendly power system and improve the noise treatment level of power transmission and transformation project, the audible noise of 9 seat substations and 13 bands transmission lines in different voltage levels are field measured and analyzed combine with the actual situation of south power system for a province. So the frequency and attenuation characteristics of the audible noise are researched based on the testing data considering the transformer, reactor, charged architecture, substation boundary and transmission lines. The testing results show that the main noise source of transmission and transformation project is the transformer, reactor and transmission lines, which the main frequency of noise is low frequency noise in substation. It can provide a basis for the substation and noise control zone design.

With the rapid development of the power grid and the increase of power demand, the voltage level of the substation is improving rapidly. The noise caused by the transformer becomes a serious problem because it affects the health of the surrounding residents. In this paper, the noise of 1000kV transformer in Shanxi is measured and analyzed. The results show that the transformer noise has low frequency characteristics, and the frequency is mainly concentrated in 100Hz and its integer times. According to the transformer noise characteristics, an adaptive active noise reduction system is designed based on least mean square (LMS) adaptive filtering algorithm. The influence of filter step size factor and filter coefficient on the convergence and stability of LMS adaptive filtering algorithm is analyzed through simulation. The active noise reduction system is built and then the noise reduction experiment is carried out. Achieved about 6 dB noise reduction.

With the rapid increase of the substation grade, the number of ultra-high voltage (UHV) transformer is increasing and the noise caused by the vibration of UHV transformer is becoming more and more serious. The vibration of UHV transformer is mainly generated from the magnetostrictive effect of the iron core and the action of the electromagnetic force of the winding. In this paper, the sound intensity and the vibration of the 1000kV UHV transformer are measured and the frequency characteristic is analyzed in detail. The vibration acceleration distribution on the oil tank surface of the transformer is measured and analyzed. The results can provide data support for the transformer noise source identification and the noise suppression measures.

The power transformer noise has become increasingly serious. The accurate measurement of transformer noise is more and more important. In this paper, the 220kV power transformer is measured with both the sound potential method and the vibration method. The measurement environment and measurement method are introduced in detail. The frequency spectrum analyses of the transformer noise and the vibration results are carried out. The relationship between the transformer noise and the vibration is studied. The research results can provide data base for noise source identification and noise suppression of the transformer.

This paper presents a new OLTC (On-load tap-changing), which can effectively solve the arcs and improve the operating speed. By using the magnetic latching relay instead of the switch, eliminating the complicated mechanical driving mechanism to shorten the voltage regulating time, reduce the failure rate and the cost; Based on the new OLTC the paper studies the automatic regulating, with a Single-Chip Microcomputer as the control chip, through designing the load voltage acquisition circuit, the switch control and power circuit, making reasonable regulating measures, writing the corresponding program to control magnetic latching relay and make the tap-changing automatically.

Recognition of human climbing fences in trans-former substations is very essential in a power substation. This paper proposed an innovative and practical human climbing fences detection method based on image processing. At first, the Gaussian Mixture Model background modelling algorithm is exploited to detect motion objects under a view of fix surveillant camera in a power substation. After obtaining the motion regions of interest, the Histogram of Oriented Gradient (HOG) feature is extracted to describe inner human. And then, based on the result of HOG feature extraction, the Support Vector Machine (SVM) is trained to classify pedestrians. Next, an improved Hough Transform is implemented to detect fences. Finally a Sparse Optical Flow method is applied to track the motion of human. Compelling experimental results demonstrated the correctness and effectiveness of our proposed method.

In HVDC monopole operation mode, there is DC flowing through AC system transformer that grounded in neutral point. Based on the maximum allowed DC current of transformer magnetic bias, the paper proposes an inversion method to deduce the maximum allowed injection current of HVDC grounding electrodes. In addition, the detail procedures to obtain maximum injection current of grounding electrodes are given. Above all, a treatment device configuration solution is given. The solution utilizes simulation operation data of AC and DC system, and it describes an assessment of the treatment.

A novel motor operating mechanism is presented which applied in the high voltage circuit breaker. The new motor is a permanent magnet motor with limited angle and only working in the starting stage. Based on the requirement of high voltage circuit breaker, the structure and parameters of motor are designed. The dynamic simulation of permanent magnet motor are achieved by employing the finite element method. The prototype of motor and drive control system are developed, established the performance testing system, and completed the dynamic characteristics testing. Finally, the winding current and angle of driving motor are obtained through the performance testing with the circuit breaker. The results indicate that the permanent magnet motor have a good mechanical characteristics and reach the operation of high voltage circuit breaker.

The high voltage (HV) motor suffers from insulation failure due to long term partial discharge (PD) which is a great threat to its normal operation. This is why online monitoring and fault diagnosis of PD activities of HV motors is becoming more and more important to date. To perform the online monitoring of the PD activity, pattern distributions of the harmful PD should be understood to guarantee detecting accuracy in the fault identification process. In this paper, three types of partial discharge, including slot discharge, bar-to-bar discharge, and corona discharge at the junction section of the semi-conductive tapes and the corona release tapes, are induced using stator coils embedded into a stator core slot model. The phase resolved partial discharge (PRPD) representation is adopted to get distribution characteristics of the PD. The PD mechanisms are illustrated using dielectric barrier discharge model. The experimental results show that a sharp increase at the onset of the positive discharge could be helpful to distinguish slot discharge from corona discharge. The relatively high amplitude and the narrow section of the phase distribution of partial discharge at the positive half voltage cycle are chosen to characterize the bar-to-bar discharge. Because of the block of insulating medium, the discharge current cannot develop into spark or electric arc but could be turned to several visible stable discharge filaments.

Stator winding vibration is the most common cause of unexpected failure of high-voltage (HV) generators. Stator bars are generally fixed in slots by using slot wedges and a side packing system. Loose slot wedges could result in excessive vibration of the stator bars, which would accelerate the deterioration of the ground wall insulation. Loose slot wedge testing is consequently one of the most important general examination procedures to make sure the condition of HV generators. The common method used for slot wedge testing is manual measurement, whereby the slot wedge is tapped by hand using a small hammer. A judgment on looseness is made based on the sound from it. A digital signal processor (DSP)-based loose slot wedge tester is described in detail in this paper, including both hardware and software design. It was developed in our laboratory based on the study of slot wedge vibration characteristics in its loosening process. Since embedded software system of the DSP is oriented to a specific industrial field while PC system is of a general purpose, the device has many advantages compared to traditional manual measurement or other slot wedge testing equipment, such as portability, high intelligence, low power consumption, etc. The tester was applied for laboratory loose slot wedge testing of a slot model. The test results soundly verified the good performance of the device.

When large generators become operational, the stator bars in the slots are subjected to the electromagnetic force during normal operation. After the generators have been operating for a long time, the electromagnetic force may cause the stator bars to vibrate due to the existence of loose stator slot wedges in large generators. This leads to mechanical abrasion of the groundwall insulation and accelerates the deterioration of the generator, and can even cause generators to fail if the slot wedges are not treated. In order to ensure large generators continue working reliably, it is essential to detect loose slot wedges in the stator slots. This paper describes the modeling of slot wedges with different fixing styles in large generators to study the process by which slot wedges become loose, and also presents an analysis of the looseness of slot wedges based on their vibration characteristics corresponding to the loosening process of the stator slot wedge. Moreover, a series of tests were performed with a nondestructive detection system developed based on this analysis to check the tightness of slot wedges in the laboratory. The results showed that loose stator slot wedges of large generators could be detected either by their vibration frequency or by their displacement amplitude. This verified the correctness of the slot wedge loosening process and the validity of the detection system.

To improve the interoperability and controllable of high voltage switch equipment, this paper puts forward the motor driver operating mechanism which applied to the circuit breaker. Developed prototype motor and drive control system, established the test system platform, selected the sensors, completed the dynamic characteristics testing. The experimental results show that the motor meet the requirements of circuit breaker in the closing and opening operation under the rated operating voltage. The voltage raises every 20V, so average closing speed 0.2m/s under the different operation voltage. The movement time of the motor drive mechanism is relatively stable under repetitive operation of the same condition. In addition, identify and extract the data that can effectively to motor design and dynamic calculation model for the calibration and verification, so as to improve the reliability and practicability for the motor design theory.

Stable operation of the power system is inseparable from the normal operation of a variety of electrical equipment; partial discharge signal power processing system to determine the time difference is the basis of the PD source localization. Typical methods of feature points difference estimate the time difference, the difference based on generalized correlation time, seek time difference based on the frequency domain, the parametric model law. In this paper, starting from two aspects, one to study the application of the theory of Hilbert - Huang transform transformer partial discharge signal spectrum and marginal spectrum analysis, and has done a simulation experiment results show that the application of the transformer partial discharge fault type the recognition is very effective; on the other hand, a partial discharge of the design expert system based on fuzzy reasoning transformer, this system is built in the traditional expert systems and fuzzy inference and fuzzy reasoning is based on the an intelligent decision-making method based on fuzzy mathematics, has been widely used in various fields, intelligent fault diagnosis of this article will be applied to the transformer partial discharge. Finally, a simulation experiment, this paper for transformer fault diagnosis, especially transformer partial discharge pattern recognition has a very important reference value.